Data carrier for chemical or biochemical analyses

ABSTRACT

The invention relates to a data carrier having memory locations to which data is written, wherein the memory locations have a number of first memory locations with erroneous data and at least one second memory location for the arrangement of analytical substances on the data carrier, wherein, when the analytical substances react with a medium that is to be investigated, the reaction product may cause a change to the data item which is written to the at least one second memory location, and the number of first memory locations is designed such that, on the one hand, when there is no reaction between the analytical substances and a medium which is to be investigated, a first data record can be determined when reading the data carrier and using a conventional error correction method, and, on the other hand, when the reaction product has caused a change to the data item which is written to the at least one second memory location, a second data record can be determined when reading the data carrier and using the conventional error correction method, with the second data record not being the same as the first data record.

The present invention describes the format for carriers for chemical orbiomedical analyses which can be read by means of conventional datareaders. In this case, parts of the redundant information which is codedon the carrier are manipulated such that a change to the data can bedetected clearly after writing. This is done by making use ofcharacteristics of the redundant information protection methods, whichoperates on small data groups. The subsequent change to the data is inthis case induced by means of a suitably designed chemical orbiochemical test on the smallest information units in the data carrier.Carriers which are designed according to this invention can be used fora large number of parallel chemical or biochemical analyses. The majoradvantage in this case is the capability to use low-cost readers fromthe consumer goods industry, without any change.

DETAILED DESCRIPTION OF THE INVENTION

With the current prior art for chemical or biomedical tests, microtiterplates or flat carriers derived from object carriers from microscopy andcomposed of plastic or glass are frequently used. For this purpose,sensor molecules are first of all immobilized in a defined arrangementin the depressions in the microtiter plates or on the surface of thecarriers. This step requires sequential pipetting or spotting methods,which are limited both in time and spatially. The smallest spotdiameters which can be held in this way have a diameter of about 80-100μm and are inhomogeneous, because of the method. In the next step, themolecules on the spots must be brought into contact with the sample tobe investigated. If the sample contains specific target molecules forthe sensor molecules, then chemical bonding takes place on the carriersurface. The bonding which takes place in this way can be detected bysuitable preparation of the sample, with the aid offluorescence-spectroscopic or photometric methods. The restrictions tothe fluorescence dyes with respect to emission intensities, quanta yieldand bleaching response result in complex detectors and apparatuses fordetaching the molecule spots which are applied to the carriers. Theinhomogeniety of the individual spots frequently results in thenecessity for subsequent, complex analysis of the primary data. Thelaboratory apparatus investment costs which result from this arerestricting the more widespread use of the new test methods to a smallnumber of fields of application such as pharmaceutical and principalresearch and, in particular, are restricting the wider use of modernmethods in biomedical test laboratories, which are subject to the evergreater demands to make savings in medical supplies. The presentinvention indicates a way in which a cost-effective analysis method canbe implemented by using established consumer goods technology andanalysis carriers matched to the respective technology.

The invention will be explained in the following text using the exampleof compact discs. However, with a small number of changes, all opticaldata carriers such as CD, CD-R, CD-RW, DVD, DVD-RW as well as magneticcarriers such as floppy discs, replaceable discs or MOD disc drives orcomparable media and their successors, which use redundant codingmethods (Reed-Solomon, CRC—cyclic redundancy check or the like), mayequally be used, in order to detect, and if appropriate to correct, alimited number of errors within defined information units.

The commercially available optical data carriers which are derived fromaudio-CDs are defined by the Philips Company Standard (Red Book,Philips). In this case, the applied information is first of allsubdivided into higher-level structures. Distinctions are drawn betweenthe so-called lead-in, table of content, data, blanks where appropriateand lead-out areas. Very small addressable data units are blocks withabout 2 kilobytes of payload data. These are in turn subdivided into 98small blocks, so-called F₃ frames, which are obtained from the originaldata using a multistage interleaving and scrambling method. One F₃ framecontains 24 bytes of payload data and 8 bytes of redundant parity data,which is calculated using the Reed-Solomon method. Audio CDs, forexample, contain 6 audio samples in each case from the right and leftaudio channels (16 bits=2 bytes) per F₃ frame. The 8 bytes of paritydata are used for error detection and error correction and included inthe stream of payload data in real time when creating CD masters.

The production of CDs is based on a predetermined set of payload data(pieces of music, programs, data, etc) which, in the end, is intended tobe recorded on the CD. First of all, in this case, a so-called glassmaster must be produced, which is used as a template for production ofinjection molds. A negative is first of all produced from this glassmaster by means of electrical nickel deposition, and a further positiveis then produced from this negative. Finally, a negative which isderived from this is used as the molding element in an injection-moldingmachine.

The glass master is provided with a thin film of photoresist and isexposed, using a so-called laser beam recorder, to a defined sequence oflight pulses on a spiral track. The sequence of light pulses is in thiscase produced by a computer program which, on the basis of the payloaddata and in accordance with the Red Book Standard, produces a series ofshifts (interleaving), codings (Reed-Solomon) and transformations(scrambling and eight-to-fourteen modulation) in real time. The outputfrom the program then controls the feed on the writing head, therotation speed of the glass master and the modulation current for thelaser beam. Since all of the control steps take place in software, it ispossible to incorporate specific algorithms which are matched to thecarrier according to the invention, by means of a simple change to thesoftware. This means that it is possible to produce carriers whichconform with the Standard, and whose specific characteristicsadditionally allow use for chemical or biochemical analysis.

Error Detection and Correction

The standard methods for error correction provide, in particular, twoperformance features:

-   -   the presence of errors and their position can be identified.    -   the order of magnitude of the errors can be determined.

These two statements are true only provided that the correction power ofthe method is not exceeded. In general, it can be stated that half asmany errors can be corrected as can be identified. However, afundamental precondition for this is that the actual payload data doesnot change, that is to say no changes occur to the data between two ormore reader processes and any such changes can be explained by readerrors.

Example of Error Correction

The example illustrates the principle which is used in the production ofthe carriers according to the invention, on the basis of a block of twodata items and two parity data items└D₁|D₂|P₁|P₂┘  (i a)

-   D₁=Data item 1-   D₂=Data item 2-   P₁=Checksum 1-   P₂=Checksum 2

The parity data is chosen such that it satisfies the following simpleequations:P ₁ =D ₁ +D ₂  (i b)P ₂ =D ₁+2D ₂  (i c)

This means that P₁ is the sum of the two data items and P₂ is the sum ofthe first data item and twice the second data item, for example└1|4|5|9┘  (ii a)

If an error is applied to one of the data items or to one of the paritydata items, then this error can be identified and corrected providedthat it is a single error, for example in this case, 6 instead of 4:[1|6|5|9]  (ii b)

That is because the equations (i) can also be formulated as follows, bysubtracting P₁ and P₂ respectively from the two sides,D ₁ +D ₂ −P ₁=0  (ii c)D ₁+2D ₂ −P ₂=0  (ii d)

In this example, it can immediately be seen that the data must beerroneous becauseD ₁ +D ₂ −P ₁=1+6−5=2  (iii a)D ₁+2D ₂ −P ₂=1+12−9=4  (iii b)

Since a value other than zero is produced in both cases, the errorcannot be in the parity data. If it were in P₁, the zero would have toappear in equation (iii b) and, conversely, in equation (iii a) if theerror were in P₂.

If equation (iii a) is subtracted from equation (iii b), then thisresults in:D ₂ −P ₁ +P ₂=6−5+9=10  (iii c)D ₁+2D ₂ −P ₂=1+12−9=4  (iii d)

The error in all these locations is accordingly in this form:[F₁/F₂|0|0]  (iii e)

That is to say:F ₁ +F ₂+0+0=2  (iii f)F ₁+2F ₂+0+0=4  (iii g)

These equations are solved to produce:F₁=0  (iii h)F₂=2  (iii i)

In consequence, we know that the error value 2 must be subtracted at thelocation of the second data item in order to obtain the original data.

Application to Chemical or Biochemical Tests

For conventional data carriers, static data is generally used, which nolonger changes after it has been written (or after the CDs have beenproduced). Each reading process should thus give the same result, exceptfor any damage to or dirt on the data carrier.

A modification to the data stream when using a predetermined errorcorrection method makes it possible to work with polymorphic data to alimited extent. This means that the data can change in a determinedmanner between two reading processes despite the error correction atindividual locations.

This is the situation, for example, when a different type ofrepresentation is scattered into the static, physically represented dataand is used for the purpose according to the invention of chemical orbiochemical verification. This may, for example, have a positive or anegative result, and a physical representation which is adequate for thedata reader must be produced in a corresponding manner after the test.The interpretation of the physical structure produced in this way isthus polymorphic as a function of the result of the chemical orbiochemical verification.

The principle of the data carriers according to the invention is now toprovide the static data deliberately with errors, which are eliminatedby the error correction method in the reader. An additional error,generated by the polymorphic representation of a chemical or biochemicaltest, then exceeds the correction capabilities of a given errorcorrection method, and the interpretation of the corrected data does notmatch the interpretation of the data without the chemical or biochemicaltest.

This makes it possible easily to distinguish between differentsituations without having to manipulate the existing correction methodswhich are implemented in standard appliances or applications. All thatis necessary is to prepare the carriers for the chemical or biochemicaltest. This allows the use of existing hardware such as CD players andderivatives as well as all known magnetic and magneto optic readers.

Example Relating to Manipulation of the Error Correction

In the method according to the invention, it is accepted that the errorcorrection capability is lost in order, instead of this, to detect achemical or biochemical reaction. The error correction is thus exchangedfor the capability to make a decision between two values at one of thefour locations. This is done by first of all deliberately applying anerror to the data[1|6|5|9]  (iii j)

From the above example, it is clear that these four values relating tothe original data:[1|4|5|9]  (iii k)can be corrected if there is only one error in one of the four dataitems. The error −2 is now additionally incorporated in the first dataitem:[−1|6|5|9]  (iii l)

The two errors exceed the correction power of the method. Nevertheless,the equations can be solved from above:D ₁ +D ₂ −P ₁=−1+6−5=0  (iv a)D ₁+2D ₂ −P ₂=−1+12−9=2  (iv b)

Analogously to the previous example, it can easily be calculated that anerror of magnitude −2 at location P₂ gives the same results in equation(iv a) and equation (iv b). This means that −2 is subtracted from P₂thus producing the supposedly correct data[−1|6|5|11]  (iv c)which now in fact contains an error in three locations.P ₁ =D ₁ +D ₂=−1+6=5  (iv d)P ₂ =D ₁+2D ₂=−1+12=11  (iv e)

Thus, summa summarum, the deliberate error in D₂ lead to a second errorin D₁ deciding whether, in the end, the original data is produced ordata which differs from the original data in three locations.

Advantages

Errors can still be identified.

Polymorphic data can be read.

Disadvantage

The error correction power is lost.

General Description of the Method

From the mathematical point of view, conventional error correctionmethods are based on the solution of equation systems for which paritydata is calculated. In general, n equations are required, when n/2errors are intended to be correctable. The equations can always bewritten in the form:f₁(x)=0f₂(x)=0f_(n−1)(x)=0f_(n)(x)=0  (v a)where x is the vector of the data including the parity data. As a rule,in comparison to the payload data, the parity data represents only arelatively small proportion of the overall data. Methods such as theseare widely used nowadays.

The class of methods described can be modified such that they can losetheir error correction power but can make use of polymorphic data forthis purpose. The modification described in the following text thereforedoes not involve the method itself, but only the data and parity data.This results in the advantage that the modification can be incorporatedin error correction methods which have been implemented in alreadyexisting applications (hardware, software, etc.).

This is based on the principle of using error correction methods whichsatisfy the following preconditions:

-   -   the correction method can be represented as an equation system        in the above form and accepts any desired input data    -   the amount of payload data is larger than the amount of parity        data.

If the data has errors at at most n locations, then the method alwaysreproduces the corrected original data. This is no longer the case iferrors occur at more than n locations.

The idea of polymorphic data storage is now to deliberately render theerror correction of the basic method inoperative. Every error correctionmethod is based on the same fundamental idea: correct data can berepresented as points in a mathematical space. The closer the points arelocated, the more similar the data items are. Between these points,there are a large number of other points which represent erroneous data,that is to say data whose parity data is not correct, that is to saythis data does not solve the associated equation system. An errorcorrection method will now always attempt to replace an erroneous datapoint by the closest correct data point in space.

If the data is deliberately manipulated such that the associated datapoint is located in the area close to the center between two or morecorrect data points in that area, small changes in the data (polymorphicdata) can lead to the input data being moved from one or other correctdata point. In the process, the correction power of the method is lost,but not the error identification.

Specific Definition

The CD will now be used as an examplary embodiment of a data carrier forthe Reed-Solomon (RS) method which is implemented at the F₃ frameslevel. An F₃ frame comprises 32 bytes of data, of which 28 bytes arepayload data and 4 bytes are parity data. The RS method allows errors inat most two bytes to be corrected. The equation system for calculationof the parity data is linear and can thus be represented as a matrixmultiplication:f(X)=0  (vi a)orM·x=0  (vi b)where M is the matrix associated with the method and x is the vectorcomprising the data. In order to avoid making the calculationunnecessarily complicated, the specific values are dispensed with here.f([D ₁ |D ₂ |D ₃ . . . D ₃₁ |D ₃₂])=0  (vi c)

Analogously to the above example, the predefined errors E₁ and E₂ areintroduced, for example, at the locations 1 and 2:f([E₁|E₂|0| . . . 0|0])≠0  (vi d)

The RS method can correct errors at a maximum of two locations and willin this situation nevertheless return the original vector, that is tosay it will correct the errors E₁ and E₂. As soon as a further error E₃is added at a third location 3, the method is overloaded and cannormally no longer carry out sensible corrections:f([E₁|E₂|E₃| . . . 0|0])≠0  (vi e)

Intrinsically, there is no gain yet. A major step now is not to takerandom values E₁, E₂, E₃, but to choose these in such a matter that, fora suitable choice of two further values E₄ and E₅, then:f([E ₁ |E ₂ |E ₃ |E ₄ |E ₅|0| . . . |0])=0  (vi f)

On the basis of the preconditions which had been placed on the method,this is possible for any given locations in the data. Since RS methodsare linear methods, then:f([E ₁ |E ₂ |E ₃|0|0| . . . |0|])=f([0|0|0|−E ₄ |−E ₅| . . . |0|0])  (vig)

The disturbance at the locations E₁, E₂ and E₃ is thus equivalent to adisturbance only at E₄ and E₅. The RS method will therefore now notcorrect the three disturbances E₁, E₂, E₃ but, in contrast, will alsoadd the additional errors E₄ and E₅. In the application, E₁ to E₅ arealready known and can be compared with the data that is read.

The correct choice of the values E₁ to E₅ depends on the specificallychosen method. In the case of linear methods, the linear equation systemcan be solved by elementary linear algebra means.

With regard to the actual application of the CD, the method describedabove still requires the solution of the problem of dirt or damage tothe CD surface, which will interfere with the method as additionalerrors.

This could be protected against by inserting further data within the F₃frame, with which, for example, it is possible to repeat the values ofthe locations 1 to 5 for additional protection. Although a readingdisturbance at any given point in the F₃ frame will now admittedlyresult in a more or less random error pattern in the data that is read,the RS method algorithm will, however, ensure that this data generallydiffers significantly from the expected data format. Although the resultof the polymorphic data item at the location 3 is thus lost, there is ahigh probability of this loss being identified so that any desiredstatistical confidence level can be achieved by multiple repetition ofthis data item. The probability of random dirt on the CD appearing tosimulate a correct result is no greater than in the case of normal CDs.With regard to CDs as data carriers, multiple repetition of this methodor of a variant is necessary, since the content of a CD is protected bya number of error correction stages.

In an extension of the procedure described above, even complex,multistage errors can be detected within a data unit. Likewise in anextension of the present invention, it is feasible to accommodate two ormore chemical or biochemical tests within one data unit. Bothpossibilities are thus part of the invention.

Addressing of Molecules on Surfaces

The method described above can now be used in the context of a chemicalor biochemical test on the CD surface. For this purpose, the intendederrors E₁ and E₂ must first of all be accommodated in the data streamwhich is applied to the CD surface in the form of pits and lands. Thisis done by means of suitable software in the described processing of thestream of payload data during the production of the glass master.Molecules which are used as a sensor during the test are then applied onthe surface of the CD in the structures which represent the data E₃. Theoptical verification method which indicates a bonded target molecule isin this case optimized for the pickup of a conventional CD player. If apositive test now takes place within the data E₃, then this isinterpreted by the decoding electronics of the CD player as an error,and the described correction method comes into action. Since all of theconditions other than E₃ are kept constant, the result of the chemicaltest in E₃ can be deduced directly from the result which is producedfrom the correction method. This makes it possible to carry out a largenumber of individual tests (approximately 30 million) in the context ofthe standard data format of CDs (Red Book). The field of application islimited only by the logistics of the different molecules and theirarrangement within the available F₃ frames. From the reader point ofview, this therefore results in the simplest feasible case, that is tosay the use of CD data and audio players which are known from consumerelectronics. There is no need to modify the software, firmware or eventhe hardware.

In addition to inorganic and organic chemical substances, biomolecules,in particular, may also be used as sensor molecules.

It is likewise possible to provide a data carrier with a predeterminednumber of memory locations with incorrectly written data, which isdesigned such that, on the one hand, the maximum number of errors whichcan be corrected using a conventional error correction method isexceeded while, on the other hand, the data record which can bedetermined after reading the data carrier and using the conventionalerror correction method is determined. On the basis of the knowledge ofthe values which have been deliberately written incorrectly to thememory locations, and knowledge of the error correction method, theerrors contained therein can be corrected retrospectively by subsequenttreatment of the data record which is determined when reading the datacarrier. In conjunction with corresponding subsequent treatmentsoftware, for example, a data carrier such as this can be used for theprotection of costly programs since the program can be read from thedata carrier without errors only by means of the subsequent treatmentsoftware.

Further features and advantages of the invention can be found in theclaims and the following description in conjunction with the drawing. Inthe drawing:

the single FIGURE shows a schematic illustration in order to illustratethe steps which are expedient for production of the data carrieraccording to the invention, and for its use.

In order to produce the data carrier according to the invention, a firstdata record 10 is stored, for example, on an optical compact disc 14, ina step 12. The first data record in this case contains so-called usefulbits and parity bits, and does not contain any erroneous data. Duringthe storage process, certain data items in the first data record 10 arechanged in a predetermined manner. For example, a value 6 is storedinstead of a value 4. The data which is stored on the CD 14 inconsequence contains errors. However, in embodiment of the invention,the number of errors is set such that it corresponds to the maximumnumber of errors which can be corrected by means of a conventional errorcorrection method. All the errors can thus be corrected by means of aconventional error correction method when reading the CD 14. Whenreading the CD 14 in the step 16 without the biochemical test in thestep 18 having been carried out, the first data record 10 is thus onceagain determined.

However, it is only of secondary importance whether the original datarecord 10 which existed before the introduction of the errors isactually determined when reading the CD 14, provided that the first datarecord that can be read in the step 16 is determined. For example, in afurther embodiment of the invention, the maximum number of errors whichcan be corrected on the data carrier can be exceeded after the data hasbeen written in the step 12. When reading the data carrier in the step16, a further, determined, first data record is then determined ratherthan the original data record. When carrying out an analysis in the step18, the data on the data carrier must in this case be modified such thata second determined data record, which is not the same as the first datarecord, is determined when reading the data carrier. For example, themaximum number of errors which can be corrected can be exceeded again bychanging the data during the analysis in the step 18.

Furthermore, in the step 12, analytical substances are applied atpredetermined memory locations on the CD 14. As has been stated, thecompact disc 14, which is provided with analytical substances and iswritten in this way can be read in the step 16 by means of acommercially available reader.

If the CD 14 is brought into contact with a medium to be investigated,for example in order to carry out a biochemical test in the step 18, theanalytical substances may react with the medium being investigated.Further process steps, for example of a chemical nature, may be requiredin the step 18 in order to result in the reaction product producing achange in the data at the memory locations which contain the analyticalsubstances. The change in the data thus results in further memorylocations with erroneous data. Since this exceeds the maximum number oferrors which can be corrected on the CD 14, a second data record 20 isdetermined rather than the original data record 10 by means of thereader after a reaction in the step 18. This second data record 20 isnot the same as the first data record 10. This second data record 20 isalso determined, since the deliberately erroneously written data, theerror correction method and the change to the data resulting from apossible reaction in the step 18 are unknown. If the second data record20 is thus determined when reading the CD 14, it can be deduced that theanalytical substance has reacted with the investigated medium.

If, on the other hand, the first data record 10 is once again determinedafter application of the substance to be investigated and after carryingout step 18, no reaction has occurred between the analytical substanceand the investigated medium, and the data on the CD 14 has not beenchanged in the step 18. The critical factor for the assessment of thebiochemical test carried out in the step 18 is thus to distinguishbetween the first data record 10 and the second data record 20.

If, in a further embodiment of the invention, the number of first memorylocations on the data carrier with incorrectly written data is less thanthe maximum number of errors which can be corrected by means of theerror correction method, two or more memory locations must be providedwith possibly different analytical substances so that, in the event of areaction at all the memory locations between analytical substances andthe investigated medium, the maximum number of errors which can becorrected is exceeded. By way of example, analyses can be logicallylinked such that the maximum number of errors which can be corrected isexceeded only when the investigated medium reacts both with a firstanalytical substance and with a second analytical substance.

However, if an undefined third data record 26 is determined when readingthe CD 14 after application of the substance to be investigated andafter carrying out the step 18, it is possible to deduce that there isan additional error which, for example, has been caused by dirt on thedata carrier. Dirt on the CD 14 or the occurrence of other errors, suchas manufacturing errors or the like, is symbolized by the step 24. Inthis case, the number of and/or the data in erroneous memory locationswill differ from the situation described above. The third data record 26determined in the step 16 thus differs not only from the original datarecord 10 but also from the second data record 20. This third datarecord 26 must be rejected as being invalid. This maintains theconfidence level against the possibility of additional errors.

In order to increase the confidence level, the same analysis is carriedout a number of times on the data carrier, and the data recordsdetermined on reading are evaluated statistically. The data records 10,20 and 26 are compared in a step 22. The comparison result in the step22 is used to determine whether the analytical substances on the CD 14have reacted with the investigated medium, that is to say whether thebiochemical test result is positive or negative, or whether the datarecord 26 is invalid.

1. A carrier for application of substances for analytical purposes,characterized by: a data track corresponding to that used in known massdata stores (CD-audio, CD-ROM, CD-R, CD-RW, DVD, magnetooptical storagemedia, hard disks, replaceable disks, all derivatives of them as well asmagnetic tapes and bar code readers), with the data track beingstructured into data blocks and optional structure elements thereof,data being represented by information units, and the information unitsbeing represented by a physical structures on the carrier, at least onepredefined information unit within at least one data block or itssubunit; the use of error correction methods, wherein parity data isused, the parity data can be calculated by solving homogeneous equationsystems, the parameters of the equation systems are parity data and/ordata, defined areas within a sequence of physical structures whichrepresent at least one information unit on which sensor molecules areimmobilized, with the result of a chemical or biochemical test which iscarried out with the sensor molecules having these additional errorsafter the test in the interpretation of the physical structures asinformation units, and/or errors which were present before the testbeing corrected after the test; a determined interaction of predefinederrors in information units and by means of errors which are produced orcorrected after a test by interpretation of areas of physical structureswhich are provided with sensor modules, such that the sum of the errorpoints and test points in information units in total exceeds thecorrection capability of the error correction method that is used; thepossibility for a unique interpretation capability of the informationunits, which are supplied from the respective reader, in a data block orits subunits with regard to the test result by comparison with apreviously known reference value, so that the characteristics of thereader have no influence on the interpretation in given error correctionmethods.
 2. The data carrier as claimed in claim 1, wherein at least onedefined error is inserted in at least one information unit within datablocks or subunits of data blocks as a function of the error correctionmethods which are used for reading the data.
 3. The data carrier asclaimed in claim 1, wherein a Reed-Solomon code is used for the errorcorrection method.
 4. The data carrier as claimed in claim 1, wherein aCRC (cyclic redundancy checksum) is used for the error correctionmethod.
 5. The data carrier as claimed in claim 1, wherein the datatrack is applied in the form of a line or a grid, in the form ofconcentric circles, in a spiral shape or in other linear or areapatterns.
 6. The data carrier as claimed in claim 1, wherein additionaldata ensures the protection of the test data against misinterpretationby dirt on the carrier surface, in particular, redundant repetitions ofthe predefined data.
 7. The data carrier as claimed in claim 1, whereinpredetermined statistical protection for the test validity is ensured bymeans of a correspondingly large number of repetitions, in particular 2to 10 7, of the individual tests.
 8. The data carrier as claimed inclaim 1, wherein quality inspection and standardization of the bondingcharacteristics of a given test can be carried out by means of standardsubstances which are applied to the carrier.
 9. The data carrier asclaimed in claim 1, wherein information about the chemical orbiochemical test which is applied to the carrier is also included in thedata.
 10. The data carrier as claimed in claim 1, wherein once thechemical or biochemical test has been carried out, parts of the carriermay also record the results which are produced by the test in accordancewith a conventional method (magnetic or magnetooptic memory, hard disks,CD-R or CD-RW and mixed forms of them).
 11. The data carrier as claimedin claim 1, in which mixed forms of at least two data memories as citedin the preceding claim may be used.
 12. A carrier having locallydifferent amounts of sensor molecules, wherein these amounts are chosensuch that the number of errors which are produced by reaction with thesensor molecules can be used to deduce the concentration of substanceswhich react with the sensor molecules.
 13. The carrier as claimed inclaim 1, wherein further data fields are included in addition to thedata fields which are used for analytical tests and include informationfor the further evaluation of the tests, in particular software forcreation of calibration curves, interpretation and analysis of data,recording of further data and its graphical representation and storage,and matching to external data from networks.
 14. A kit, including themajor substances for carrying out one or more analyses with the carrieras described in claim
 1. 15. A data carrier having memory locations towhich data is written, wherein the memory locations have a number offirst memory locations with erroneous data and at least one secondmemory location for the arrangement of analytical substances on the datacarrier, wherein, when the, analytical substances react with a mediumthat is to be investigated, a reaction product may cause a change to thedata item which is written to the at least one second memory location,and the number of first memory locations is designed such that, on theone hand, when there is no reaction between the analytical substancesand a medium which is to be investigated, a first data record can bedetermined when reading the data carrier and using a conventional errorcorrection method, and, on the other hand, when the reaction product hascaused a change to the data item which is written to the at least onesecond memory location, a second data record can be determined whenreading the data carrier and using the conventional error correctionmethod, with the second data record not being the same as the first datarecord.
 16. The data carrier as claimed in claim 15, wherein theerroneous data has predetermined values, such that both the first datarecord and the second data record are determined.
 17. The data carrieras claimed in claim 15, characterized in that the number of first memorylocations with erroneous data corresponds to the maximum number oferrors which can be corrected by the error correction method.
 18. Thedata carrier as claimed in claim 15, characterized in that two or moresecond memory locations are provided with analytical substances, withthe analytical substances reacting in different second memory locationsfor different concentrations of the medium that is to be investigated.